17-(dimethylaminoethylamino)-17-demethoxygeldanamycin and Adenocarcinoma

Topics: Adenocarcinoma; Apoptosis; Benzoquinones; Cell Line, Tumor; Deoxycytidine; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Fluorouracil; Gemcitabine; HSP90 Heat-Shock Proteins; Humans; Inhibitory Concentration 50; Lactams, Macrocyclic; Molecular Targeted Therapy; Neoplasm Proteins; Pancreatic Neoplasms; Recurrence

Ovarian carcinoma is initially sensitive to platinum-based therapy, but become resistant over time. The study of cancer sensitizing substance is therefore the major challenge for a number of scientific groups. Our experiments were carried out on human ovarian adenocarcinoma A2780cis cells resistant to cisplatin and their response to 2-(4'fluoro-phenylamino)-4H-1,3-thiazine[6,5-b]indole (thiazine[6,5-b]indole) and/or heat shock protein (Hsp) 90 inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) using proliferation assay, cell cycle analysis and monitoring of apoptosis were examined. A2780cis cells revealed the same fold of resistance to Hsp90 inhibitor 17-DMAG as it is declared for cisplatin (18 times), but only 3.2 times for thiazine[6,5-b]indole. Our results showed that the combination of thiazine[6,5-b]indole and 17-DMAG significantly reduced proliferation of A2780cis cells and led to their accumulation in G2/M phase of the cell cycle. Moreover, both thiazine[6,5-b]indole as well as 17-DMAG increased the number of annexin V positive A2780cis cells in time dependent manner. Interestingly, thiazine[6,5-b]indole treatment significantly activated also caspase-3 compared to untreated or 17-DMAG-treated cells and reduced mitochondrial membrane potential (MMP) of A2780cis cells with more significant decline after combined treatment. In this regard, the incubation of A2780cis cells with thiazine[6,5-b]indole induced PARP protein cleavage as well as an increased level of Bad protein with more pronounced changes after combined treatment. Importantly, Hsp70 protein was not upregulated in A2780cis cells neither by individual treatment nor by mutual combination. Our results signify antiproliferative and pro-apoptotic effects of novel thiazine[6,5-b]indole potentiated by Hsp90 inhibitor 17-DMAG in ovarian adenocarcinoma cells resistant to cisplatin and therefore represents new strategy in cancer treatment.

Topics: Adenocarcinoma; Antineoplastic Agents; Benzoquinones; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cisplatin; Dose-Response Relationship, Drug; Female; HSP90 Heat-Shock Proteins; Humans; Indoles; Lactams, Macrocyclic; Ovarian Neoplasms; Thiazines

The three major clinically relevant mechanisms of acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in EGFR mutant lung cancer are a second mutation in the EGFR gene (T790M), Met amplification, and increased expression of hepatocyte growth factor (HGF). Heat shock protein90 (Hsp90) is a 90 kDa molecular chaperone for proteins that include EGFR, Met, and echinoderm microtubule-associated proetin-like-4-the anaplastic lymphoma kinase. Here, we determined whether inhibition of Hsp90 could overcome HGF-triggered EGFR-TKI resistance in EGFR mutant lung cancer cells.. The effects of the Hsp90 inhibitor 17-demethoxygeldanamycin (17-DMAG) on the growth of lung cancer cells resistant to the EGFR-TKI were examined in the presence and absence of HGF, and in cells transfected with the HGF gene in vitro and in vivo.. EGFR-TKI erlotinib did not inhibit the growth of HGF-gene transfected Ma-1 (Ma-1/HGF) cells and H1975 cells, containing the EGFR L858R and T790M mutations, respectively. Erlotinib also did not inhibit the growth of PC-9 and Ma-1 cells, with deletions in EGFR exon19, in the presence of HGF. However, 17-DMAG induced apoptosis and markedly inhibited the growth of these cell lines, even in the presence of HGF. This inhibition by 17-DMAG was associated with decreased expression of EGFR and Met in tumor cells. An in vivo model of HGF-triggered erlotinib-resistance, which used Ma-1/HGF cells, showed that 17-DMAG markedly suppressed tumor growth by decreasing angiogenesis and increasing apoptosis.. Hsp90 inhibitors may overcome HGF-triggered resistance to EGFR-TKIs and may result in more successful treatment of patients with EGFR-mutant lung cancers.

Topics: Adenocarcinoma; Animals; Apoptosis; Benzoquinones; Blotting, Western; Drug Resistance, Neoplasm; ErbB Receptors; Female; Hepatocyte Growth Factor; HSP90 Heat-Shock Proteins; Humans; Lactams, Macrocyclic; Lung Neoplasms; Mice; Mutation; Prognosis; Protein Kinase Inhibitors; Tyrosine; Xenograft Model Antitumor Assays

Heat shock proteins (Hsps) are protective in models of transplantation, yet practical strategies to upregulate them remain elusive. The heat shock protein 90-binding agent (HBA) geldanamycin and its analogs (17-AAG and 17-DMAG) are known to upregulate Hsps and confer cellular protection but have not been investigated in a model relevant to transplantation. We examined the ability of HBAs to upregulate Hsp expression and confer protection in renal adenocarcinoma (ACHN) cells in vitro and in a mouse model of kidney ischemia-reperfusion (I/R) injury. Hsp70 gene expression was increased 30-40 times in ACHN cells treated with HBAs, and trimerization and DNA binding of heat shock transcription factor-1 (HSF1) were demonstrated. A three- and twofold increase in Hsp70 and Hsp27 protein expression, respectively, was found in ACHN cells treated with HBAs. HBAs protected ACHN cells from an H2O2-mediated oxidative stress, and HSF1 short interfering RNA was found to abrogate HBA-mediated Hsp induction and protection. In vivo, Hsp70 was upregulated in the kidneys, liver, lungs, and heart of HBA-treated mice. This was associated with a functional and morphological renal protection from I/R injury. Therefore, HBAs mediate upregulation of protective Hsps in mouse kidneys which are associated with reduced I/R injury and may be useful in reducing transplant-associated kidney injury.

Topics: Adenocarcinoma; Animals; Benzoquinones; Cell Line, Tumor; Disease Models, Animal; Enzyme Inhibitors; Heat-Shock Proteins; HSP27 Heat-Shock Proteins; HSP70 Heat-Shock Proteins; HSP90 Heat-Shock Proteins; Humans; Kidney; Kidney Neoplasms; Lactams, Macrocyclic; Male; Mice; Mice, Inbred BALB C; Molecular Chaperones; Neoplasm Proteins; Oxidative Stress; Reperfusion Injury; RNA, Small Interfering